/*    $OpenBSD: fvwrite.c,v 1.14 2005/08/08 08:05:36 espie Exp $ */
/************************************************************************
 * Copyright (c) 1990, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 ************************************************************************/


#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "errno.h"
#include "local.h"
#include "fvwrite.h"

/*
 * Write some memory regions.  Return zero on success, EOF on error.
 *
 * This routine is large and unsightly, but most of the ugliness due
 * to the three different kinds of output buffering is handled here.
 */
 int
__sfvwrite(FILE *fp, struct __suio *uio)
{
    size_t len;
    const char *p;
    struct __siov *iov;
    int w, s;
    char *nl;
    int nlknown, nldist;

    if ((len = uio->uio_resid) == 0)
        return (0);
    /* make sure we can write */
    if (cantwrite(fp)) {
        errno = EBADF;
        return (EOF);
    }

#define    MIN(a, b) ((a) < (b) ? (a) : (b))
#define    COPY(n)      (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))

    iov = uio->uio_iov;
    p = (const char *)iov->iov_base;
    len = iov->iov_len;
    iov++;
#define GETIOV(extra_work) \
    while (len == 0) { \
        extra_work; \
        p = (const char *)iov->iov_base; \
        len = iov->iov_len; \
        iov++; \
    }
    if (fp->_flags & __SNBF) {
        /*
         * Unbuffered: write up to BUFSIZ bytes at a time.
         */
        do {
            GETIOV(;);
            w = (*fp->_write)(fp->_cookie, p, len);
            if (w <= 0)
                goto err;
            p += w;
            len -= w;
        } while ((uio->uio_resid -= w) != 0);
    } else if ((fp->_flags & __SLBF) == 0) {
        /*
         * Fully buffered: fill partially full buffer, if any,
         * and then flush.  If there is no partial buffer, write
         * one _bf._size byte chunk directly (without copying).
         *
         * String output is a special case: write as many bytes
         * as fit, but pretend we wrote everything.  This makes
         * snprintf() return the number of bytes needed, rather
         * than the number used, and avoids its write function
         * (so that the write function can be invalid).
         */
        do {
            GETIOV(;);
            if ((fp->_flags & (__SALC | __SSTR)) ==
                (__SALC | __SSTR) && fp->_w < (int)len) {
                size_t blen = fp->_p - fp->_bf._base;
                unsigned char *_base;
                unsigned int _size;

                /* Allocate space exponentially. */
                _size = fp->_bf._size;
                do {
                    _size = (_size << 1) + 1;
                } while (_size < (unsigned int)(blen + len));
                _base = (unsigned char *)realloc(fp->_bf._base, _size + 1); /*lint !e586*/
                if (_base == NULL)
                {
                    errno = ENOMEM;
                    goto err;
                }
                fp->_w += (int)_size - fp->_bf._size;
                fp->_bf._base = _base;
                fp->_bf._size = (int)_size;
                fp->_p = _base + blen;
            }
            w = fp->_w;
            if (fp->_flags & __SSTR) {
                if ((int)len < w)
                    w = len;
                COPY(w);    /* copy MIN(fp->_w,len), */
                fp->_w -= w;
                fp->_p += w;
                w = len;    /* but pretend copied all */
            } else if (fp->_p > fp->_bf._base && (int)len > w) {
                /* fill and flush */
                COPY(w);
                /* fp->_w -= w; */ /* unneeded */
                fp->_p += w;
                if (fflush(fp))
                    goto err;
            } else if ((int)len >= (w = fp->_bf._size)) {
                /* write directly */
                w = (*fp->_write)(fp->_cookie, p, w);
                if (w <= 0)
                    goto err;
            } else {
                /* fill and done */
                w = len;
                COPY(w);
                fp->_w -= w;
                fp->_p += w;
            }
            p += w;
            len -= w;
        } while ((uio->uio_resid -= w) != 0);
    } else {
        /*
         * Line buffered: like fully buffered, but we
         * must check for newlines.  Compute the distance
         * to the first newline (including the newline),
         * or `infinity' if there is none, then pretend
         * that the amount to write is MIN(len,nldist).
         */
        nlknown = 0;
        nldist = 0;    /* XXX just to keep gcc happy */
        do {
            GETIOV((nlknown = 0));
            if (!nlknown) {
                nl = (char *)memchr((void *)p, '\n', len);
                nldist = nl ? nl + 1 - p : (int)len + 1;
                nlknown = 1;
            }
            s = MIN((int)len, nldist);
            w = fp->_w + fp->_bf._size;
            if (fp->_p > fp->_bf._base && s > w) {
                COPY(w);
                /* fp->_w -= w; */
                fp->_p += w;
                if (fflush(fp))
                    goto err;
            } else if (s >= (w = fp->_bf._size)) {
                w = (*fp->_write)(fp->_cookie, p, w);
                if (w <= 0)
                    goto err;
            } else {
                w = s;
                COPY(w);
                fp->_w -= w;
                fp->_p += w;
            }
            if ((nldist -= w) == 0) {
                /* copied the newline: flush and forget */
                if (fflush(fp))
                    goto err;
                nlknown = 0;
            }
            p += w;
            len -= w;
        } while ((uio->uio_resid -= w) != 0);
    }
    return (0);

err:
    fp->_flags |= __SERR;
    return (EOF);
}
